Energy Deposition at the Bone-Tissue Interface from Nuclear Fragments Produced by High-energy Nucleons

Abstract

The transport of nuclear fragmentation recoils produced by high-energy nucleons in the region of the bone-tissue interface is considered. Results for the differential flux and absorbed dose for recoils produced by 1-GeV protons are presented in a bidirectional transport model. The energy deposition in marrow cavities is seen to be enhanced by recoils produced in bone. Approximate analytic formulae for absorbed dose near the interface region are also presented for a simplified range-energy model.

A general solution of the time-independent forward Boltzmann equation for high energy 4He and its secondaries through bulk matter

“…Wilson [2][3][4][5] and Cucinotta [1,[6][7][8][9][10] demonstrate that equation (1) may be reexpressed as follows:…”

Dose Equivalent Near the Bone-Soft Tissue Interface from Nuclear Fragments Produced by High-Energy Protons

“…Outsidq the earth's magnetosphere, target fragments contribute: on the order of 60 mSv y-l to a crew's total dose eqqivalent, even when heavy shields mediate (Townsend eti al. The secondary radiation environment reated by 1 GeV protons interacting with tissue near e bone-soft tissue interface also has been investigate i (Cucinotta et al 1990). The effects on the absorbed dos& near boundaries of dissimilar materials have been know to have important consequences in photon, neutron, a d charged particle exposures of some body tissues (S iers 1964b, 1969Lawson 1967;Whitwell and piers 1976;Bhatia and Nagarajan 1979;Chen and oston 1982).…”

“…Target fragment LET spectra and dose equivalent are determined as a function of distance from a bone-soft tissue interface. The energy limits in eqn (1) are as given by Cucinotta et al (1990). 1, it is assumed that a high-energy fluence of nucleons, 4, passes normally through two distinct regions separated by an interface.…”

“…1, it is assumed that a high-energy fluence of nucleons, 4, passes normally through two distinct regions separated by an interface. The solution for fluence +(x,E), the inclusive fragmentation cross sections (Bertini 1970;Silberberg et al 1976) and target fragment momentum distribution (Wilson et al 1989) have been previously described (Wilson 1983;Cucinotta et al 1990). The fluence of target fragment isotopes, j , in medium 1 along a ray passing normally through the interface is where x is a point in region 1 through which a ray passes.…”